1. Field of the Invention
The present invention relates to a torque sensor assembly for a power-assisted bicycle, especially to a torque sensor assembly detecting torque applied by a rider. Then an electric motor drives the bicycle according to the torque detected and provides assisting power to overcome the drag caused by the terrain or any sort of load change by the rider or the bicycle.
2. Description of the Prior Art(s)
Beyond human-powered, a bicycle may also be powered by an electric motor which delivers auxiliary traction power to assist a rider, especially when the bicycle is riding up an upward terrain or when the rider is getting tired. A power-assisted bicycle that still requires the rider's pedaling for activating the electric motor is known as a “pedelec.” To assure the rider's safety when riding the power-assisted bicycle, some countries have instituted rules and regulations to regulate use of the power-assisted bicycle, such as a travel speed and assisted power limits
One conventional model is by detecting the wheel speed of the bicycle to determine when to switch on electric motor and start supplying the auxiliary traction power which also have multiple levels of assisted power options available. However, that sort of bicycle controller considers neither varying loads nor the rider's weight for estimation, which can always have the required assistance power miscalculated. Another model that determining the assisting power by various wheel speed presets is also often used for power-assisted bicycles on the market.
However, merely the wheel speed cannot necessarily reflect the correct required assisting power. That is, any preset motor power output without taking the actual load and rider's weight data for real-time regulations can never correctly reflect the true assisting power required.
To overcome the defects, the present invention provides a torque sensor assembly for a power-assisted bicycle to mitigate or obviate the aforementioned problems.